Rice is the staple food crop for more than half of the world population. Thus, rice varieties enriched with various micronutrients qualifies as a better alternative to combat micronutrient deficiency. The present investigation was undertaken to study the variability, heritability and genetic divergence for grain characters especially grain Zinc (Zn) content and grain Iron (Fe) content in 30 genotypes of rice. Among the 30 genotypes that were under investigation, the Phenotypic Coefficient of Variation (PCV) values were found to be higher than that of Genotypic Coefficient of Variation (GCV) values for all the traits. High heritability (>60%) was observed for all the studied traits. Days to 50% flowering showed highest heritability (99.1%) followed by test weight (94.8%) and grain Fe content (94.8%). The genetic advance as percent of mean ranged between medium (10%-20%) to high (>20%) with grain yield per plant showing the highest GAM (40.84%) followed by test weight (38.56%) and grain Zn content (33.73%). These 30 genotypes were assigned into groups of 11 clusters using Tocher’s method. Cluster I comprised of the most number of genotypes with 18 genotypes followed by Cluster V with 3 genotypes while the remaining 9 clusters were monogenotypic. Days to 50% flowering was found to have the highest contribution towards genetic divergence. These findings indicated that the genotypes under study have sufficient trait variability and varietal diversity which could be exploited in crop improvement programmes aimed at developing Zinc (Zn) and Iron (Fe) biofortified varieties.

Brown spot disease in rice is caused by Cochliobolus miyabeanus (Anamorph: Bipolaris oryzae (Breda de Haan) Shoemaker, 1959 (Synonyms: Helminthosporium oryzae). It causes significant losses by affecting both economic yield and grain quality. Though, it is a minor disease in most of the parts of the world but the historical famines like Krishna Godaveri Delta famine and Bengal famines and huge crop losses in a number of incidences as in Guyana and Nigeria renders it as a potential threat to rice crop and adverted the requirement of efficient, sustainable and economical strategies to cope with the pathogen. In this context, availability of resistant sources against the pathogen is a noteworthy alternative for disease management. Realising the importance of resistant sources, the present research investigation was undertaken to study association between resistance to brown spot disease and yield attributing traits in rice via correlation studies and path analysis to identify high yielding resistant lines for brown spot disease in rice. In this study disease resistance expressed in terms of AUDPC showed negative correlation with yield and yield attributing traits and direct negative effect on yield. Thus, AUDPC can be utilised as a selection parameter for developing improved cultivars with higher grain yield and lower susceptibility towards the brown spot pathogen.

The present study was undertaken with the objective to assess the nature and magnitude of gene action for various morpho-physiological and biochemical traits in two crosses namely cross BHU 31 × HD 2733 and cross, HPYT 485 × HD 2967 in wheat. The six basic generations (P1, P2, F1, F2, B1 and B2 obtained from these crosses (made in Rabi 2018 and 2019) were evaluated for 13 quantitative traits including yield and micronutrient traits during Rabi 2020 in compact family block design with 3 replications at Research farm, RPCAU, Pusa and data were recorded on randomly selected plants per replication of each cross for all the traits. The estimation of micronutrient in wheat grains was done by X-Ray Fluorescence Spectrometry at Harvest-plus Division, ICRISAT, Hyderabad. The result regarding gene effect indicated that in both the crosses dominance and dominance × dominance effect for grain Zinc content (-29.00 & 19.18 and -9.79 & 7.04 respectively in cross I and II) and grain Iron content (-18.16 & 12.37 and -20.29 & 12.31 respectively in cross I and II) has significant role in expression of these traits. Duplicate type of gene interaction was found predominant for grain Zinc and Iron content and almost for all the traits due to opposite sign of dominance (h) and dominance × dominance (l) gene effect which tends to cancel the effect of each other in hybrid combination therefore selection should be advanced in later generation.